Rio Blast is a member of the heroic warriors, a cowboy warrior with an arsenal of laser guns and blasters built into hidden cavities within his chest and knees, which he unleashes upon unsuspecting opponents. He also carries a pack of blasters on his back, which he pulls over his head during battle to become a one-man army of laser blasters. He has a cybernetic hand attachment the is a fairly large gun. Though many foes underestimate the simple appearance and cocky bravado of the young Master known as Rio Blast, many more have quickly learned that beneath his rough exterior and dangerous smile lurks an entire hidden arsenal. A cyborg equipped with retracting blasters, even the hardest targets cannot escape the blazing gunfire and trick shots of this Eternian desperado!

Origin #1 (UK Magazines - Files Of Scrollos):

Rio Blast. He was originally a member of the Starband Marshalls, on a world called Loredos. Many of the people on Loredos came to great wealth when a type of mineral called Feridium was discovered- but this soon led to chaos as many criminals came after the Feridium- and they were sent by Horde Prime! Rio at that time was a young farm hand, whose family's home was destroyed when they could not pay their taxes to the Red Indian criminals. Rio began to train to be a warrior, and became a lawman who saved many people from the Red Indians with his amazing gun skills. Horde Prime decided that Rio must be destroyed, and enacted a cunning plan. Rio was called to assist a villager whose son had been playing in a mine but had never come out. Rio went in there to find the man's son- but the man was in fact one of the criminals, and together with some Indians, shot at the mine shaft, which collapsed on Rio. But the man instantly regretted helping the criminals, and helped some men dig Rio out. Rio was badly hurt, so a scientist turned him into a cyber-defence machine with built-in lasers, to save his life. Rio defeated many of the criminals with his new body lasers, then one day was sent out to help an astro-jail above Loredos. But Horde Prime, who realized he had lost control of Loredos, was so angry that he used his Magna-ray to direct a meteor at the planet, blowing it up! But Rio was not on Loredos, so he survived, and a fragment from the exploding planet knocked him to Eternia, where he joined the heroic warriors to help pay back Horde Prime.

Origin #2 (MOTUC Bios)

With the ability to transform from a normal warrior into an awesome arsenal of fire power, Rio Blast is in all ways the fastest draw in the universe. As the sole survivor of a group of heroic explorers from Loredos in a starband near Eternia, Rio ended up as the "law" in that lost frontier. Flung by a meteorb to the surface of Eternia, Rio allied himself with the renegade Masters of the Universe in their battle against evil. Rio Blast is nagged by the fact that he has left behind an untamed starband and he often chomps at the bit to get back. He-Man promised to aid Rio Blast back home as soon as the warriors of Skeletor have been defeated once and for all. Rio Blast transforms into a One-man arsenal to get the drop on enemies!